This invention relates to the field of therapeutic medical devices. More particularly, this invention relates to a temperature controlled fluid therapy system utilizing sensors to provide signals to a continuously variable pump which cycles fluid therapy to an individual.
Hot and cold therapies have been used for many years to treat physiological maladies. Ice, one of the more traditional cold therapy methods has the advantage of minimal cost and is easily manufactured. However, traditional ice application methods are not perfect, many patients complaining about leaky ice bags and the inconvenience of refilling the ice bag as the ice melts. Furthermore, traditional ice application methods are not very precise in applying a uniform temperature throughout the injured area. Likewise, the applicator temperature is not easily regulated.
Various mechanical cold and hot therapy systems have been developed to surmount some of the problems associated with the more traditional therapeutic techniques. Continuous flow cold therapy devices utilize a pump to force temperature regulated fluid through a xe2x80x9cblanketxe2x80x9d or applicator which, in turn, is applied to a patient. However, not all of these mechanical fluid therapy systems give a constant temperature regulation which may be deleterious to patient recovery. Additionally, current temperature sensors are susceptible to the presence of a liquid, resulting in operational fluctuations, unrelated to temperature. These fluctuations make it impossible to control the system temperature precisely.
There is a need for an improved fluid therapy system including improved temperature sensor systems that are inexpensive and not amenable to fluid contamination.
The foregoing and other needs are met by a temperature controlled therapy device according to the present invention. The temperature controlled therapy device is designed to maintain a desired temperature in a fluid, depending on a user""s preference of a hot or a cold therapy treatment. The device includes a fluid reservoir, preferably containing a temperature controlled fluid. The reservoir has an entry and an exit port allowing the fluid to circulate from the reservoir to a watertight blanket. The blanket has an internal space for circulating the fluid therethrough and an entry and an exit port in fluid communication with the reservoir entry and exit ports, respectively. A conduit is connected between the exit port of the reservoir and the entry port of the blanket and between the exit port of the blanket and the entry port of the reservoir. The conduit defines a fluid circuit wherein the temperature controlled fluid circulates from the reservoir to the blanket and from the blanket to the reservoir. The device utilizes a pump to circulate the temperature controlled fluid through the fluid circuit. The device also utilizes a differential temperature sensor to generate an output signal which is proportional to a difference in fluid temperature in the blanket and a temperature at a remote location. An absolute temperature sensor generates an output signal that is proportional to the temperature at the remote location. The outputs from the differential temperature sensor and the absolute temperature sensor are input to a control circuit. The control circuit uses these inputs to generate a control signal which controls the operation of the pump and thereby maintains a defined temperature range within the fluid in the blanket. A power supply supplies power to the device.